Poor Gas Mileage.


Information and questions on GL1500 Goldwings (1988-2000)
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GeezerGoldwing
Posts: 10
Joined: Thu Dec 03, 2015 10:39 pm
Location: Alvin, Texas
Motorcycle: 1989 Goldwing 1500

Poor Gas Mileage.

Postby GeezerGoldwing » Mon Dec 14, 2015 9:58 pm



1989 GW 1500... had to keep choke on to keep it running,. flushed tank and fresh gas with sea foam and star tron added... pinged and panged then begin to run better. Finally was able to turn off choke and it idled pretty steady.. then began to surge.. kept it running.. after about a tank of gas thru carbs. i decided to check the carb synch.. it was way off... 13in on one side and 5in on the other side.. synched it and it ran better.. Finally with a good idle, i filled the tank with fresh gas, more sea foam and took off.. it tries to die at stop signs and red lights. I went 34 miles at 60 to 70 mph and used almost all the fuel in a full tank.. any suggestions where to start trying into this bad boy. Found several vaccum lines either bent, broke or cracked. replace all them.. one thing my auto **** is bypassed, the vaccum line is plugged and laying in the frame .. could that be any problem.. thanks guys for any info.. man this website rocks... love it.. thanks again.



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seelyark1
Posts: 465
Joined: Sun May 27, 2012 1:57 pm
Location: Dunnellon, Florida
Motorcycle: 2000 GL1500 SE
1998 GL1500 SE Totaled
1984 VT500C
1967 CB550-4

Re: Poor Gas Mileage.

Postby seelyark1 » Tue Dec 15, 2015 7:05 pm

one thing my auto **** is bypassed, the vaccum line is plugged and laying in the frame

Read more: viewtopic.php?t=31078#ixzz3uRADcAYv
What is this? Hard to try to diagnose your problem as we have no idea what you are trying to tell us, but there should be no vacuum hose plugged and laying on the frame. It should be connected somewhere. Btw, welcome to the site. I'm sure the people here will try to help you out. :)
Ride safe, and smart. Asphalt is like #1 grit sandpaper. Dave

GeezerGoldwing
Posts: 10
Joined: Thu Dec 03, 2015 10:39 pm
Location: Alvin, Texas
Motorcycle: 1989 Goldwing 1500

Re: Poor Gas Mileage.

Postby GeezerGoldwing » Tue Dec 15, 2015 7:28 pm

It's the auto fuel on unit It must be bad so THE Vaccum Line Is plugged..Gas Goes straight From tank to carbs.

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ct1500
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Location: Glastonbury,CT
Motorcycle: 1988 GL1500
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Re: Poor Gas Mileage.

Postby ct1500 » Tue Dec 15, 2015 8:29 pm

Changing sync is the last thing you want to do on a crappy running engine. All you did was bias the engine towards the better bank of cylinders so it runs a little better. Sync is the last thing to be done on a well running engine and is the icing on the cake.

You have underlying ignition and/or carburetor problems that need addressing.
Last edited by ct1500 on Tue Dec 15, 2015 8:35 pm, edited 1 time in total.
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ct1500
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Re: Poor Gas Mileage.

Postby ct1500 » Tue Dec 15, 2015 8:33 pm

GeezerGoldwing wrote:It's the auto fuel on unit It must be bad so THE Vaccum Line Is plugged..Gas Goes straight From tank to carbs.


That is how a fuel system works gas flows from tank to carbs, the petcock only closes when engine is off. :?:
This is what I do
Local and need repair help with your 1500, Valkyrie or ST please PM

GeezerGoldwing
Posts: 10
Joined: Thu Dec 03, 2015 10:39 pm
Location: Alvin, Texas
Motorcycle: 1989 Goldwing 1500

Re: Poor Gas Mileage.

Postby GeezerGoldwing » Tue Dec 15, 2015 10:22 pm

I kinda figured it was a ignition and or carb problem. What is your recommendation.

And I know about the flow of gas. My question is the vaccum line that operates it is off and plugged with a bolt. Can that affect performance? Thanks for your replies. .

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seelyark1
Posts: 465
Joined: Sun May 27, 2012 1:57 pm
Location: Dunnellon, Florida
Motorcycle: 2000 GL1500 SE
1998 GL1500 SE Totaled
1984 VT500C
1967 CB550-4

Re: Poor Gas Mileage.

Postby seelyark1 » Tue Dec 15, 2015 10:26 pm

First off, I would repair the "auto fuel valve" so that the fuel starvation can go away. This valve is supposed to open with that vacuum line so it can supply fuel to the engine. It does not gravity feed the carbs. Then we can work from there.
Ride safe, and smart. Asphalt is like #1 grit sandpaper. Dave

GeezerGoldwing
Posts: 10
Joined: Thu Dec 03, 2015 10:39 pm
Location: Alvin, Texas
Motorcycle: 1989 Goldwing 1500

Re: Poor Gas Mileage.

Postby GeezerGoldwing » Tue Dec 15, 2015 11:28 pm

Thank you, ordering repair kit now. Thanks again.

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spiralout
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Motorcycle: 1975 GL1000 (gone)
1980 GL1100I (with '77 1000 engine)
1996 GL1500 SE

Re: Poor Gas Mileage.

Postby spiralout » Wed Dec 16, 2015 1:06 pm

GeezerGoldwing wrote:My question is the vaccum line that operates it is off and plugged with a bolt. Can that affect performance? Thanks for your replies. .

No, not as long as there's no vac leak in the plugged off line.
seelyark1 wrote:First off, I would repair the "auto fuel valve" so that the fuel starvation can go away. This valve is supposed to open with that vacuum line so it can supply fuel to the engine. It does not gravity feed the carbs. Then we can work from there.

Bypassing the petcock isn't going to cause fuel starvation and rebuilding it, even though it should be done, won't fix OP's problem. Like ct1500 said, it's an ignition or carburetion issue.




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